The coordinates a(0, 0), b(0, 3), c(4, 3) and d(4, 0) are graphed and connected together. what 3-dimensional shape will be created when this shape is rotated about the y-axis? provide an explanation and proof for your answer to receive full credit.

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.